Rafa Benitez's future as Newcastle boss was in doubt on Tuesday when takeover talks with prospective buyer Amanda Staveley collapsed.

Newcastle owner Mike Ashley and Staveley’s Middle East investment fund PCP Capital Partners have been involved in negotiations since November, but Ashley has lost patience and a source said the talks had been a ‘complete waste of time’.

It leaves question marks over Benitez, given his concern that Ashley’s ambition does not match his own. Any transfer deals now are likely to be loans.

Rafa Benitez's future as Newcastle manager was in doubt on Tuesday night

Amanda Staveley's potential takeover of Newcastle has collapsed but club remains for sale

Staveley had been in negotiations with top-flight club's owner Mike Ashley since November

Newcastle’s owner let it be known on Tuesday he has grown exhausted with the Yorkshire-born financier and PCP Capital Partners, her Middle East investment fund who are said to have offered around £250million for the club.

But Ashley also has concerns about the legitimacy of the bid and sources have even accused Staveley of only being interested in the publicity around a proposed deal. Ashley is also said to be unhappy with the manner in which negotiations have been played out in public.

From now on Ashley will only talk to interested parties who first make a cash deposit to prove their intentions are genuine.

Those close to Staveley say their offer remains on the table and insist they are serious about buying the club. However, they will have to return with a significantly improved package if there is to be progress.

Magpies owner Ashley called off takeover talks after labelling Staveley's bid a 'waste of time

It leaves manager Rafa Benitez with an owner who wants to sell and who is reluctant to invest in the squad this month, although the Spaniard has now been given the green light to make three signings given the threat of relegation. They, however, are likely to be loan deals.

News of the takeover collapse comes just over a month after Ashley and Staveley met at an Indian restaurant in London, sparking hope of a deal in the region of £300m. Sources close to Staveley said at the time they were concerned about the team’s position in the Premier League and wanted clauses included to allow for a reduced price should Newcastle go down.

There were no updates over Christmas but Ashley returned from a holiday in Miami last week hoping to make progress in his effort to end his 10-year association with the club.

Those close to Staveley, meanwhile, say their offer to buy the club remains on the table

But it would appear he has now given up on Staveley and sources close to the sports retail tycoon told Sky: ‘It is only right to let the fans know that there is no deal on the table — or even under discussion — with Amanda Staveley and PCP. Attempts to reach a deal have proved exhausting, frustrating and a complete waste of time.’

It leaves question marks over Benitez’s future, especially given his feeling that Ashley’s ambition does not match his own.

Sportsmail revealed on Friday that a second Dubai-based group are monitoring the situation. They, too, have concerns over the club’s status beyond this season and say they will hold off from making concrete their interest.

But Ashley will not tolerate any parties he believes to be time-wasters and, at present, there are no other offers on the table.

It leaves Rafa Benitez with an owner who wants to sell and who is reluctant to invest in squad

Newcastle are three points above relegation zone and Benitez wants new players this month